Strukturen aus AIB2− und BaAl4−analogen Einheiten. I Die Verbindungen Sr4Pd5P5 und Sr2Pd3P3

Structures with AIB₂? and BaAl₄?type Units. I The Compounds Sr₄Pd₅P₅ and Sr₂Pd₃P₃ Sr₄Pd₅P₅ (Cmcm, a = 4.177(1) Å, b = 31.377(5) Å, c = 8.581(2) Å, Z = 4) und Sr₂ Pd₃P₃(Pmmm, a = 4.199(1) Å, b = 4.212(1) Å, c = 34.227(4) Å, Z = 4) have been prepared by heating the elements. Both structures contain exclusively units characteristic for the AIB_2? and BaAl₄?type. The ratio between isolated P-atoms and P₂?pairs is interpreted with an ionic splitting of the formulas.     

Über die Synthese von Erdalkalimetalldihalogeniden und die Strukturen von Ca3Br2CBN und Sr3Cl2CBN

On the Synthesis of Alkaline-Earth Dihalides and the Structures of Ca₃Br₂CBN and Sr₃Cl₂CBN The reaction of alkaline-earth carbonates with ammonium chloride or bromide yields alkaline-earth dihalides at relatively low temperatures (300°C). Ca₃Br₂CBN and Sr₃Cl₂CBN were synthesized in sealed niobium containers at 950°C from the metal, its dihalide, boron nitride and graphite. The crystal structure of Sr₃Cl₂CBN was refined from single crystal data. Sr₃Cl₂CBN crystallizes isotypic with Ca₃Cl₂CBN in the orthorhombic space group Pnma (No. 62) with a = 1448.4(2) pm b = 405.46(5) pm, c = 1170.0(1) pm. The lattice constants of Ca₃Br₂CBN and Sr₃Cl₂CBN were determined by orthorhombic indexing of the powder patterns (Ca₃Br₂CBN: a = 1444.3(2) pm, b = 390.64(6) pm, c = 1139.2(2) pm; Sr₃Cl₂CBN: a = 1444.0(4) pm, b = 405.27(8) pm, c = 1167.8(2) pm). There was no success in preparing homologues with Barium.     

New Fluoromanganate(III) Hydrates: Mn3F8 · 12H2O and AgMnF4 · 4H2O

Single crystals of fluoride hydrates Mn₃F₈ · 12 H₂O and AgMnF₄ · 4 H₂O have been prepared and characterized by X-ray methods. Mn₃F₈ · 12 H₂O crystallizes in the space group P1 (a = 623.0(3), b = 896.7(4), c = 931.8(4) pm, α = 110.07(2)°, β = 103.18(2)°, γ = 107.54(2)°, Z = 1); AgMnF₄ · 4 H₂O crystallizes in the space group P2₁/m (a = 700.9(2), b = 726.1(1), c = 749.4(3) pm, β = 107.17(3)°, Z = 2). Both structures contain Jahn-Teller-distorted [Mn(H₂O)₂F₄]^? anions as well as crystal water molecules and exhibit a complex hydrogen bond network between anions and cations, i. e. [Mn(H₂O)₆]²⁺ for the first and a polymeric [Ag(H₂O)₂]^? cation for the second compound.     

Über die Reaktion von Tellur mit Wolframhalogeniden: Synthese und Struktur von Te7WOCl5, einer Verbindung mit einem polymeren Tellur-Kation

On the Reaction of Tellurium with Tungsten Halides: Synthesis and Crystal Structure of Te₇WOCl₅, a Compound with a Polymer Tellurium Cation The reaction of tellurium with WOCl₄ in the presence of a large excess of WCl₆ in a sealed evacuated glass ampoule at 150°C yields beside the main product Te₈(WCl₆)₂ a small amount of Te₇WOCl₅. The crystal structure determination (orthorhombic space group Pcca, lattice parameters at 173 K: a = 2 596.5(9) pm, b = 810.0(3) pm, c = 775.7(2) pm) shows that Te₇WOCl₅ is built of one-dimensional band shaped polymeric tellurium cations, one-dimensional associated pyramidal WOCl₄^? anions and of isolated Cl^? anions. Te₇WOCl₅ can thus be formulated as [Te₇²⁺]_n [WOCl₄^?]_n (Cl^?). The structure is closely related but not isotypic to the bromine containing analogue Te₇WOBr₅. The difference between the two structures lies in different directions of the polar [WOX₄^?]_n chains (X = Cl, Br). The strongly elongated thermal ellipsoid of one tellurium atom is shown to be caused by thermal vibration by determing the crystal structure of Te₇WOCl₅ at three different temperatures (223, 173 and 123 K). All displacement parameters of all atoms can be extrapolated to zero for 0 K.     

Nd4Ti9O24: Präparation und Struktur

Preparation and Crystal Structure of Nd₄Ti₉O₂₄ The compound Nd₄Ti₉O₂₄ was prepared by heating mixtures of Nd₂O₃/TiO₂ (1 : 4.5) at temperatures of T = 1 330°C in air (2× 1d). Single crystals of Nd₄Ti₉O₂₄ were obtained by chemical transport reaction (T₂→T₁; T₁ = 1000°C, T₁ = 900°C, 14 d) using chlorine (p(Cl₂, 298 K) = 1 atm) as transport agent with Nd₄Ti₉O₂₄ as starting material. Nd₄Ti₉O₂₄ crystallizes in the orthorhombic space group Fddd (No. 70) with a = 13.9926(11) Å, b = 35.2844(21) Å, c = 14.4676(17) Å (Z = 16). The structure was refined to give R = 4.0% and R, = 3.7%. Main building units are TiO₆ octahedra, NdO₆ distorted square antiprisms and NdO₆ octahedra.     

Die Kristallstrukturen von α- und β-K3OCl

The Crystal Structures of α- and β-K₃OCl The orange coloured compound K₃OCl has been prepared. It exists in a low temperature modification (α-K₃OCl) and a high temperature modification (β-K₃OCl). The transition temperature is 364 ± 5 K. The crystal structures were determined by x-ray diffraction. α-K₃OCl crystallizes at room temperature in the orthorhombic space group Pbnm (Z = 4) with the cell parameters a = b = 723.9(2) pm and c = 1 027.7(2) pm in the anti-GdFeO₃-structure type. The high temperature modification β-K₃OCl crystallizes (Z = 1) in the cubic space group Pm3m in the β-Ag₃SI-structure type with a = 516.2(2) pm (T = 393 K).     

Über den Einfluß von Substitution auf die Kristallstruktur von SrNi2P2

About the Effect of Substitution on the Crystal Structure of SrNi₂P₂ With several series of mixed crystals the effect of substitution on the crystal structure of SrNi₂P₂ (polymorphic, the structures are variants of the ThCr₂Si₂ type) is investigated by X-ray methods. In the compound Ni completely can be substituted by Co and Cu respectively and also P by As; in Sr_1–xCa_xNi₂P₂ there is a gap of the miscibility between 0.3 ≤ x ≤ 0.6. A low substitution of the several elements more than proportionally changes the structure parameters. In this range the mixed crystals with Ca, Cu, and As, respectively, undergo first order phase transitions with significant changes of the bond distances, which will be interpreted by the results of band structure calculations.     

Synthese und Eigenschaften von Sr3Mo1.5Zn0.5O7‐δ, einer Phase mit perowskitverwandter Schichtstruktur

Synthesis and Properties of the Layered Perovskite Phase Sr₃Mo_1.5Zn_0.5O_7‐δ The new layered perovskite phase Sr₃Mo_1.5Zn_0.5O_7‐δ was synthesized by solid state reaction using a Zn/ZnO oxygen buffer. The crystal structure was refined from X‐ray powder pattern by the Rietveld method. The compound crystallizes tetragonal in the space group I4/mmm (no. 139) with the lattice parameters a = 3.9631(3) Å, c = 20.583(1) Å. An oxygen deficiency corresponding to δ ≈ 0.25 was determinated, indicating the presence of molybdenum in mixed valence (Mo⁴⁺ and Mo⁶⁺).     

Struktur einer kristallinen Hochtemperaturmodifikation des Calciumultraphosphats,CaP4O11, und die kristallographische Orientierungsbeziehung zur Raumtemperaturphase

Structure of a High Temperature Modification of Calciumultraphosphate, CaP₄O₁₁, and its Crystallographic Orientation Relation with Respect to the Room Temperature Phase The title compound was obtained by heating a mixture of CaCO₃, P₄O₁₀ in excess and H₃PO₄ in excess as well to 500°C and annealing for 10 days. The Calciumultraphosphate, CaP₄O₁₁, transforms at 85°C in a hot nitrogen gas stream into a second modification with orthorhombic space group (Aba2), the structure of which was determined: a = 12.683 Å, b = 12.090 Å, c = 12.627 Å, Z = 8, layer structure, R = 0.034. The crystallographic orientation relation between the two phases of CaP₄O₁₁ was determined.     

Einkristall-Röntgenstrukturanalyse von Sr3TiGa10O20

Single Crystal X-Ray Analysis of Sr₃TiGa₁₀O₂₀ Single crystals of Sr₃TiGa₁₀O₂₀ were prepared by recrystallisation of a molten oxide mixture and investigated by X-Ray technique. It crystallizes with monoclinic symmetry, space group C–C2/m, a = 15.451, b = 11.579, c = 5.051 Å, β = 108.57°, Z = 2. Sr₃TiGa₁₀O₂₀ belongs to the Pb₃GeAl₁₀O₂₀ type, showing Ga³⁺ in tetrahedral and octahedral coordination. The octahedral coordinated point positions are occupied by Ga³⁺ and Ti⁴⁺ statistically.     

Zur Darstellung und Struktur neuer Niobate LnNb7O19 (Ln = La,Ce)

Preparation and Structure of LnNb₇O₁₉ (Ln = La, Ce) Two new ternary compounds, LaNb₇O₁₉ and CeNb₇O₁₉, could be prepared and characterized. At temperatures about 900°C already decomposition of both compounds will be initiated, but at lower temperatures (800°C) no reaction between the binary components occured. Single crystals could be obtained by chemical transport reactions (T₂ → T₁; T₂ = 800°C; T₁ = 780°C). Chlorine for mineralization or as transport agent is absolutely indispensable for preparation. Single crystal investigations on LaNb₇O₁₉ (R = 4.4%; R_w = 4.19%) result in the trigonal space group P3. The cell dimensions are a = 6.2531(2) A; c = 20.0685(10) Å; Z = 2. The structure can be described as to be build up by layers of 8-coordinated La and 6-coordinated Nb, alternating with layers of edge-sharing pentagonal NbO₇-bipyramids. Corresponding to the unusual sequence of layers the structure of LnNb₇O₁₉ (Ln = La,Ce) is the first example of a trigonal member of a family of structures, which has been described in detail by Jahnberg. The most examples are represented by tantalates, but only a few niobates related to these structures are known.     

Synthese und Struktur von (Ph3PAu)3Mn(CO)4

Synthesis and Structure of (Ph₃PAu)₃Mn(CO)₄ Photolysis of (Ph₃PAu)Mn(CO)₅, Ph₃PAuN₃ and Ph₃PAuNCO yields (Ph₃PAu)₃Mn(CO)₄ ( 1 ). 1 crystallizes in the monoclinic space group P2₁/n with a = 1 031.3(1); b = 3 095.2(3), c = 3 386.3(3) pm; β = 97.58(3)°; Z = 8. The crystal structure contains two symmetry independent clusters 1 of the same geometry. Their inner core MnAu₃ forms a rhombus with distances Mn? Au of about the same lengths between 258.4(4) and 262.0(4) pm. The distances Au? Au range from 276.6(2) to 281.3(2) pm. The bonding in 1 is discussed and compared with those of (Ph₃PAu)₃Co(CO)₃ having the same total number of electrons but a tetrahedral framework.     

Chemischer Transport und Struktur von UNb2O7 – einem neuen MM′2O7-Typ

Chemical Transport and Structure of UNb₂O₇ – a New Type of MM′₂O₇ Powdery UNb₂O₇ could be obtained by heating an äquimolar mixture of UO₂ and Nb₂O₅ in an evacuated silica tube at 1 100°C. Chemical transport in a small temperature gradient with NbCl₅/Cl₂ as transport agent was successfully used for crystal synthesis. UNb₂O₇ crystallizes with orthorhombic symmetry; the lattice constants are a = 3.8012(7) Å; b = 21.170(8) Å; c = 6.440(2) Å and Z = 4. Structure determination in the space group Cmcm (nr. 63) let to R = 0.021 (R_w = 0.019). U and Nb1 have CN = 7, Nb2 has CN = 6 (5 + 1). Uranium is surrounded by oxygen like an doma-octahedron, niobium1 like an pentagonal-bipyramid and niobium2 like an distorted octahedron.     

Zum thermischen Verhalten von Li3MnO4. II [1, 2]. Über α- und β- Li2MnO3

Thermal Behaviour of Li₃MnO₄. II. α- and β-Li₂MnO₃ By thermal decomposition of Li₃MnO₄ we obtained two new forms of Li₂MnO₃: α-Li₂MnO₃ crystallizes due to Guinier-Simon photographs cubic face-centered with a = 4.09₂ Å, β-Li₂MnO₃ hexagonal with a = 4,93, c = 14.24 Å, c/a = 2.89. α-Li₂MnO₃ is paramagnetic with μ = 3,82 B.M. Below the Neel temperature (≈? 50 K) β-Li₂MnO₃ is antiferromagnetic. Effective Coordination Numbers, ECoN, are calculated and discussed.     

Über die Magnetischen Eigenschaften der Cobaltate Na6CoS4, Na6CoSe4 und K6CoS4

Magnetic Properties of the Cobaltates Na₆CoS₄, Na₆CoSe₄, and K₆CoS₄ The alkali metal cobalt chalcogenides Na₆CoS₄, Na₆CoSe₄, and K₆CoS₄ crystallize in the space group P6₃mc with Z = 4. The structure is characterized by isolated [CoX₄]-tetrahedra. The magnetic susceptibilities show Curie-Weiss behaviour. The deviations at low temperatures are caused by antiferromagnetic interactions. The magnetic moments are discussed with regard to ligand-field parameters.     

Über die Halogenaminierung von Diseleniden. Synthese und Struktur des achtgliedrigen Ring-Kations [Me2SN2SeMe]2++

On the Haloamination of Diselenides. Synthesis and Structure of the Eight-membered Ring Cation [Me₂SN₂SeMe]₂⁺⁺ N-halogen compounds of benzamidine and S,S-dimethylsulfone diimides react with diselenides by Se? Se-bond cleavage yielding different types of selenium-nitrogen compounds. With N-bromo-benzamidine the diazene derivatives RSeN(Ph)CN?NC(Ph)NSeR 2a, b (a : R = Me; b : R = Ph) are formed. In the reaction of N,N′-Dichloro-S,S-dimethylsulfone diimide, Me₂S(NCl)₂, with diselenides cyclic hetero-selenonium salts [(Me₂SN₂SeR)Cl]₂ ( 4a, b ) are obtained. The structure of the eight membered ring compound 4a was determined by x-ray crystallography (space group P1 , Z = 1) and compared with that of the isotypic sulfonium salt [(Me₂SN₂SMe)Br]₂ ( 3a ).     

Preparation of Y2Ba4Cu7O15-δ Superconductor without High Oxygen Pressure

The synthesis of bulk Y₂Ba₄Cu₇O_15-δ superconductor at atmospheric oxygen pressure via solid state sintering is reported. Temperature ranging from 860 to 890 °C as well as time interval over 2 to 15 days were used to investigate the formation of the Y₂Ba₄Cu₇O_15-δ phase. A time-temperature profile characterizing the conditions for the preparation of Y₂Ba₄Cu₇O_15-δ phase suggests the optimal condition to be sintering at 890 °C for over 10 days. Detailed results of X-ray diffraction, electrical resistivity, iodometric titration and magnetization measurements are described.     

Über die Kristallstruktur von Barium-Acetylendicarboxylat Monohydrat – Ba[C2(COO)2] · H2O

On the Crystal Structure of Barium Acetylene Dicarboxylate Monohydrate – Ba[C₂(COO)₂] · H₂O Ba[C₂(COO)₂] · H₂O crystallizes in the monoclinic space group P2₁/a. The lattice constants are a = 753.4(2), b = 921.8(2), c = 881.8(2) pm and β = 102.00(2)°. The crystal structure is characterized by an intricate three-dimensional framework made up by Ba²⁺ and [C₂(COO)₂]^2? ions. Ba²⁺ has coordination number 9 and is bound to two water molecules and seven oxygen atoms belonging to carboxylate groups of the dianion. The [C₂(COO)₂]^2? ion does not merely act like a multiple monodentate ligand, but coordinates Ba²⁺ in a chelate-like manner as well. The carboxylate groups of the dianion are inclined to each other by 65°.